A crystal oscillator circuit consists of a feedback network with an amplifier or a gain element and a crystal. Historically both of these two building blocks were designed and manufactured by companies specializing in frequency control products. However this paradigm has changed as separate companies design and manufacture crystals and amplifiers. This has generated problems with matching the amplifier, or gain element, with the crystal.
An important factor for having a well-functioning crystal oscillator is that a supply voltage for the amplifier should at least roughly match a drive level of the quartz crystal, otherwise the crystal will have problem with achieving the target frequency and experience accelerated aging. There are different solutions explained in the prior art to match the supply voltage with the drive level of the crystal and a solution often recommended by the suppliers is to use a so called Pierce oscillator circuit with the addition of a damping resistor. The damping resistor will indeed damp the supply voltage for the crystal. However it will also affect the oscillation capabilities of the crystal. That is an oscillation margin will decrease and in some cases imply that the crystal does not start oscillating at all.